WateringTimesWatering plan, $19
Carissa macrocarpa 'Prostrata', WUCOLS IV

How often to water prostrate Natal plum in California

In July on the north-central coast, established prostrate Natal plum in loam needs a deep soak only about once a month or less: about 2.2 gallons each time for a plant 2 feet across. Prostrate Natal plum is a low, spreading form of a spiny evergreen shrub from coastal South Africa. Its glossy, leathery leaves cover a dense mat, and fragrant white star flowers appear much of the year, followed by edible red fruits. It takes salt spray, sun or light shade, and it wants well-drained soil.

Ground coverRated for 4 of 6 zones

How often to water prostrate Natal plum, month by month

Your city
Plant width
2 ft
Your soil

Type your city above and the days between waterings and the gallons appear here, worked out from your city's climate table. Or read the figures by climate zone further down.

Every month, on your water days. The personal plan prints this for prostrate Natal plum and the rest of your yard, on the days your water supplier allows.Get the plan for $19

How this is worked out: established roots fill the top 1.5 feet of soil, and you water again when that soil has dried halfway. Loam soil holds about 1.5 inches of water per foot. Water the whole area the plant covers, and skip a watering after a good soaking rain.

Which soil do you have?

Dig down a few inches, take a handful of moist soil and squeeze it.

  • Sandy: gritty, falls apart when you open your hand, will not form a ball.
  • Loam: forms a soft ball that crumbles when you poke it.
  • Clay: forms a firm, sticky ball and squeezes out into a ribbon between thumb and finger.

Still not sure? Pick loam. Most garden beds sit between sand and clay.

How to measure plant width

A shrub with its width marked from one side to the other and the circle under it shaded blue

Measure across the plant, from the tips of the leaves on one side to the tips on the other.

Water the whole area the plant covers, shown in blue. The gallons here cover that area.

A wider plant means more gallons each watering, not more waterings. While it is young, measure again each spring.

How to tell it needs water

  • Soil dry 3 inches down under the mat in summer signals prostrate Natal plum needs water
  • Glossy leaves turning dull and curling slightly in heat can indicate thirst
  • Flowers and young fruit dropping during a long dry spell can follow a dry root zone
  • Yellowing leaves and stem dieback over soggy soil point to poor drainage

How to water it

  • Water under the mat with drip lines tucked beneath the branches
  • Soak 8 to 10 inches down, then let the top couple of inches dry before the next soak
  • Plant in sun to light shade in well-drained soil, including sandy seaside ground
  • Mulch between young plants until the branches knit into a cover
  • Move drip lines outward as the low branches spread

Through the seasons

Water a new planting regularly through its first summer as branches spread. Established mats take deeper soaks less often and handle short dry spells. It is evergreen and can flower almost year round, so it never fully rests. Winter rain covers most needs near the coast. WUCOLS rates prostrate Natal plum low water on the north-central coast and the south coast. It gets a moderate water rating in South Inland and the low desert. WUCOLS marks it as not suited to the Central Valley or the high desert.

In pots

Prostrate Natal plum trails nicely from a large container or raised planter, which also keeps its spines away from bare legs. Water when the mix is dry an inch or two down, soaking until it drains. In summer heat that can be every few days. Empty the saucer afterward. Trim stems that grow past the rim. In cold inland spots, move the pot under cover on frosty nights.

1 Your climate zone six WUCOLS zones, each from its own reference city
Not ratedWUCOLS does not rate Prostrate Natal Plum for the Central Valley zone
A year
no figure
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses

WUCOLS lists Prostrate Natal Plum as not suited to this region for the Central Valley zone, so no monthly figure is computed here.

Monthly water need by climate zone

Prostrate Natal Plum: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.15–0.310.78–0.78
Feb0.21–0.320.87–0.93
Mar0.35–0.461.3–1.52
Apr0.47–0.561.61–1.95
May0.58–0.641.95–2.45
Jun0.64–0.692.29–2.79
Jul0.64–0.792.51–2.85
Aug0.6–0.742.33–2.6
Sep0.5–0.61.86–2.08
Oct0.35–0.461.33–1.49
Nov0.19–0.330.9–0.96
Dec0.12–0.260.68–0.68
Year4.8–6.218.41–21.08

How this is worked out: the WUCOLS water rating for each zone times that zone’s climate for the month. A dash means WUCOLS does not rate the plant there. The figures are what the plant uses, before sprinkler losses.

Plants with the same water needs 4

Rated not suited to this region in the Central Valley, like prostrate Natal plum. Plants that drink alike can share one valve and one schedule.

Japanese ArdisiaArdisia japonicanot rated, Central Valleyno Central Valley ratingSwedish IvyPlectranthus verticillatusnot rated, Central Valleyno Central Valley ratingWhite CloverTrifolium repensnot rated, Central Valleyno Central Valley ratingCoral VineAntigonon leptopusnot rated, Central Valleyno Central Valley rating
Minutes for your sprinklers

Turn this into minutes on your water days

Every city page has a calculator that takes prostrate Natal plum, your sprinkler type and the month, and gives the minutes per water day for that supplier's schedule. Or put it in a zone of the personal watering plan and get all twelve months printed.

Questions people ask

How often should I water prostrate Natal plum in summer?

In July, established prostrate Natal plum in loam needs a deep watering about every 27 days on the south coast and about every 9 days in the South Inland zone. Sandy soil holds less water, so waterings come closer together. Clay stretches them. Check the soil before each watering and skip one after a soaking rain.

How much water does prostrate Natal plum need per day?

In July on the north-central coast, established prostrate Natal plum needs about 0.1 gallons a day for a plant 2 feet across and about 0.3 gallons a day for a plant 4 feet across. Give it in deep waterings spread days apart rather than a little every day, so the whole root zone gets wet.

Does watering for prostrate Natal plum change across California?

Yes. WUCOLS rates prostrate Natal plum separately for each of the six California climate zones: low water in the North-Central Coastal zone, not suited to this region in the Central Valley zone, low water in the South Coastal zone, moderate water in the South Inland zone, not suited to this region in the High and Intermediate Desert zone, moderate water in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.

Is Natal plum fruit edible?

Yes, the red, plum-like fruits are edible when ripe. Other parts of the plant carry a low poison rating. Pick only fully colored fruit.

Does prostrate Natal plum have thorns?

Yes, the branches carry stout, often forked spines up to an inch long. Plant it away from paths where people brush past. Wear gloves when pruning.

Can Natal plum grow by the ocean?

Yes, it is a good seaside plant and tolerates salt spray. Sandy, well-drained soil suits it. Check young plants more often in wind.

Can Natal plum take frost?

It is a tropical shrub suited to the mildest, nearly frost-free gardens. Hard frost can damage it. Cover low mats or move pots on cold nights.

Does prostrate Natal plum need much pruning?

Only light pruning is needed to keep edges neat. It takes shearing well. Prune after a flush of flowering.

More plant watering guides

Milk BushBoojumOcotilloSilver TreeNew Zealand Christmas TreeTanbark OakPygmy Date PalmBristlecone Pine

Sources